Occasionally destructive fires erupt when oil and/or gas are allowed to flow freely from their wellheads and either accidentally or as has happened in Kuwait, these oil and/or gas flows are intentionally set on fire. In the past it has been possible in some instances to extinguish such fires by lowering a drum, loaded with as much as 400 lbs. of a detonating explosive charge into the stream jetting from the wellhead and exploding the charge in the flame. The shock wave resulting from the tremendous explosion violently blasts everything near the center of the explosion and often times the fire is snuffed out. However, this procedure is only successful on smaller types of fires.
Other attempts have been made to extinguish such fires by injecting water or carbon dioxide, or other fire extinguishing chemicals either into the entire body of flames or into the oil well casing near the outlet end of the oil well to produce a non-combustible mixture together with the oil and/or gas flowing under pressure from the wellhead or in an attempt to dilute the fuel and/or cool the fuel in the burning oil and/or gas stream to a temperature below its autoignition temperature. Such procedures are based on the principle of putting out the fire at the wellhead by in effect diluting the flow of the oil and/or gas fuel to the flames to a degree to make the entire mixture incombustible.
Examples of certain of these systems are described in the following issued United States patents:
______________________________________ 703,832 Rigby July 1, 1902 1,640,839 Kliewer August 40, 1927 3,070,172 Carter, Jr. December 25, 1962 3,463,227 Smith August 26, 1969 3,620,299 Wiseman, Jr. November 16, 1971 3,685,584 Gracia August 22, 1972 3,763,936 Menage October 9, 1973 4,316,506 Poole February 23, 1982 4,899,827 Poole February 13, 1990 ______________________________________
It is well known that high explosives have been used adjacent to and within the flames at the wellheads of the flaming oil and/or gas wells in an attempt to snuff out the flame. As is evident from the continuing disaster in Kuwait, when the size of the flame becomes too large, this procedure is no longer satisfactory. In fact according to news reports from that area, only a small number of the less vigorous flames at these well heads have been extinguished to date.
A variation of this explosive extinguishing technique is shown in the U.S. Pat. No. 3,070,172. This patent contains a description of a method for attacking oil well fires and the like by use of a bomb like container filled with a fire extinguishing material such as CO.sub.2 under pressure which explodes when the bomb is heated by the flames. The violence of the explosion is alleged to be effective to suppress the fire and the rapid exhaustion of the gaseous material that is released from within the bomb causes a chilling of this flame in an attempt to suppress the flame. Further, the non-flammable CO.sub.2 gas itself assists in smothering the flame. It is doubtful however that a sufficiently large CO.sub.2 bomb could be prepared and used successfully against large oil and/or gas well blazes that would be more powerful than the currently used 400 lbs. or larger detonating explosive charges used in the pure explosive charge procedure; in either case great dangers are encountered.
The group of U.S. Pat. Nos. 1,640,839; 3,463,227; 3,763,936; 4,316,506 and 4,899,827 all show examples of apparatuses designed to mix a fire extinguishing material in the flow of the oil and/or gas gushing from a wellhead that is burning in an uncontrolled flame above the wellhead. In these teachings it is variously proposed to provide an apparatus that is built into the wellhead or outlet from the well, which apparatus is particularly adapted to inject either water, steam, liquid and gaseous CO.sub.2 and mono-potassium phosphate mixture, nitrogen, monoammonia phosphate, and possibly other known fire extinguishing chemicals or mixtures thereof directly into the oil and/or gas stream issuing from the well. In all of these patents the use of an apparatus is required that includes a structure built into the wellhead piping arrangement that can be used should the necessity arise for introducing a fire extinguishing substance into the flowing stream to be mixed with the oil and/or gas, so that as stated in U.S. Pat. No. 3,763,936 col. 2, lines 1-5, "a turbulent zone is created artificially across the whole of the mixture of fuel and extinguishing fluid upstream of the flame and downstream of the zone in which the extinguishing fluid is injected, to give a homogeneous mixture at the base of the flame."
Other fire extinguishing apparatuses built into a wellhead or surrounding the head are shown in U.S. Pat. Nos. 703,832 and 3,620,299 wherein a stream of steam and CO.sub.2 respectively are driven under pressure into contact with a gushing stream of oil and/or gas. The earlier patent includes a valve structure adapted to be closed to shut off an oil flow and incidentally includes a bare description of a means for discharging steam "therefrom for extinguishing the flames when from any cause the oil or gas flowing from the well becomes ignited." See page 1, lines 15 to 18. The later patent shows means for injecting a fire extinguishing material into the well casing and for surrounding a gushing oil well flow with means for dispensing liquid CO.sub.2 from several manifolds installed around the wellhead to displace oxygen in the surrounding atmosphere and wherein the "extinguishing fluid is injected into the well casing to be mixed with gas and oil as they are being blown from the well". See Col. 1, lines 56 to 58.
Another fire extinguishing apparatus adapted only for use in connection with oil and gas wells drilled in water covered areas is shown in U.S. Pat. No. 3,685,584. This patent describes a water spraying means that produces a dome-shaped curtain of water that is directed to cover the entire oil well platform and drilling rig on the platform. The water is sprayed from nozzles supported on a pair of arcuate float structures that can be moved into position and bolted together to surround the platform and produce a circular or other shape water curtain over the entire oil well platform structure. It is said that this continuously formed curtain or water shield will aid in cutting off the supply of oxygen and extinguish the flame.